The invention supplies a quantity Q of gas while dividing at flow rate ratio Q1/Q2 from a gas supply facility equipped with a flow controller. A total quantity Q=Q1+Q2 of gas is supplied into a chamber at flow rate Q1 and Q2 through shower plates fixed to ends of branch supply lines by providing open/close valves with a plurality of branch supply lines GL1 and GL2, respectively, to supply the specified quantity of gas from the gas supply facility, and by utilizing bypass line BL1 on the downstream side of the open/close valve OV1 and branched from GL1, bypass line BL2 on the downstream side of the open/close valve OV2 and branched from GL2, pressure type division quantity controller connected to the bypass line BL1 and the bypass line BL2, a sensor measuring pressure inside branch supply line GL1, and another sensor measuring pressure inside branch supply line GL2.